Mike McDonnell, a former Democrat who crossed to the Republican party this year, said he would not vote to change the midwestern state’s distribution of electors to the same winner-takes-all process that operates in most of the US.
It comes down to one man. I think the sticking point for him is the fact of the pure opportunism & gamesmanship of changing the state EC voting system a mere 43 days before the election. He's evidently a Republican convert, but not all the way MAGAt - yet.
Nebraska had, at one time, a strong reform impulse, under the late great Norris - partitioning the EVs into congressional districts was seen as a movement to 'one person, one vote' - it was seen to be, and in fact is, a pro-democracy measure.
Supposedly, this guy McDonnell wants to run for mayor of Omaha. So he probably doesn't want to end up on their bad side through supporting a blatantly partisan stunt like this. It'd be ironic that Trump's election chances are hindered by another craven political opportunist.